What should I look for when buying straps? I was never a fan of them but Ive just come to a point in which I simply cannot progress in my DLing because of constant grip failures. Tips? Any particular brand?

I've used 2 different type, simple canvas and rubber on one side. The rubber helps a litte but it's not a big deal. Since I'm prone to losing them, I just go with the cheapest, something like this:
Mine are by Grizzly and they're dirtier than those pictured.

Stu Ward
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Let thy food be thy medicine, and thy medicine be thy food.~Hippocrates
Strength is the adaptation that leads to all other adaptations that you really care about - Charles Staley
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Thanks TimD

I've used simple canvas straps with a loop tied in one end. I've heard or read that a simple piece of seat belt material works well. I think Wendler uses that. The ends are laid together and wrapped around the bar.

Other thoughts for grip work:
Use double overhand grip for as much of your DLing as you can, changing to mixed grip when you have to.
Doing "grip holds" which are essentially a very high rack pull held for time. MattZ does this. Look at his training log to see where he has taken his grip. He holds way more than his DL, double overhand.

I once saw a guy using straps on the pec deck! I wanted to say something, but he looked a lot stronger than me.

Our greatest fear should not be of failure, but of succeeding at things in life that don't really matter.--Francis Chan